During the delivery of liquids, such as water, it may be desirable to treat the liquid before it reaches a user or consumer. For instance, a user may wish to treat water at a point of entry or a point of use to incorporate or remove certain additives. Some additives, such as chlorine or chloramine, may already be incorporated into a domestic water supply. These additives may serve to disinfect or sanitize the water supply. However, these additives may also present certain drawbacks to a user. For instance, the presence of chlorine and/or chloramine is known to affect the taste of water. As a result, a user may wish to remove or neutralize these additives before using the water, e.g., for drinking, washing, or cooking.
Some existing systems provide porous filtration devices to passively treat or remove additives from water. Although porous filtration devices may be able to filter out certain larger additives, their efficacy is often limited by the pore size of the associated filtration media and/or the contact time of water with the filtration media. In general, particle exclusion filtration does not remove dissolved contaminants. Increasing the efficacy of such devices often results in undesirably increasing upstream water pressure and/or decreasing downstream water pressure. Moreover, increasing efficacy of the filtration system may greatly increase the time needed to treat the water, i.e., the time needed before the water is ready for use. These pressure variations and increases in treatment time may render the systems otherwise unusable for many applications.
In some instances, it may be possible to provide an active treatment system to actively inject one or more neutralizing or removal agents into a water flow. For instance, an automated pump may be provided to selectively inject a dosing agent into a water flow. However, such systems would necessarily require an active (e.g., mechanical and/or electronic) pump and/or controller apparatus. Multiple mechanical and/or electronic parts may increase the system's overall complexity, as well as the risk that the system may break.
Accordingly, a passive system for fluid treatment would be desirable. In particular, it would be desirable to have a passive system for dosing a liquid, such as water, flowing through the system without the use of additional active components.